Flat airstone will gradually diffuse air into the tank, attaching an air stone makes the water circulation much better. Adding an air stone will keep the water cleaner, provide the fishes with more oxygen, and it has a lot of health benefits for aquatic life.
Soak your airstone in tank water for an hour, then attach tubing to it and turn on the pump.
*Product may vary from image shown
McMerwe’s comment: An airstone can greatly improve the overall look of your aquarium. Providing water movement in the aquarium for fish to swim through. Excellent aerators in your aquarium [Rating 5/5]